After the Asian Financial Crisis (AFC) of 1997-99, a dominant orthodoxy arose both in regional diplomatic circles and the regional scholarship that analysed it, that the Association of South East Asian Nations (ASEAN) had established the institutional basis both for South East Asian as well as East Asian political and economic integration. Thus, at the beginning of the new millennium, Peter Katzenstein declared that East Asian regional integration was “an idea whose time has come.” Indeed, it was widely assumed that an expanded ASEAN machinery would “socialize the [East Asian] region with the same norms and values that have proved successful in Southeast Asia.” In view of these large claims about ASEANs apparent centrality to regional security in Southeast Asia, and its procedurally driven transformation of foreign relations across East Asia in the twenty-first century, the uncertainty among its diplomats and its academic admirers in the context of China’s rise and growing regional assertiveness represents something of a puzzle. To unravel this puzzle, we shall argue that ASEAN remains what it essentially was from its inception, namely an association of weak states created to achieve the limited purpose of maintaining regional order. Yet, even in this endeavour the arrangement has proved of limited effectiveness. Mean-while, its attempt to export its norms to the wider region have rendered it vulnerable to the incursion and hegemony of more powerful regional actors. To explore the limitations of Asian regionalism, the paper will focus on 2 areas of ASEAN policy formation since the AFC: the attempt to build an integrated ASEAN economic community and to establish a framework to address overlapping claims to the South China Sea. The dissonance between ASEANs rhetoric and its limited achievements in these areas leaves it increasingly sidelined by the evolution of great power rivalry in the Asia Pacific.